Secondary seal for floating tank roofs



J. H. WIGGINS SECONDARY SEAL FOR FLOATING TANK ROOFS Sept. 9, 1 947.

Filed June 26,'l944 2 Sheets-Sheet l FIGQZ;

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INVENTOR. JOHN H. WIGGINS W M fir A TTOENEY Sept. 9,- 1947.

J. H. WIGGINS SECONDARY SEAL FOR FLOATING TANK ROOFS 1 Filed June 26, 1944 2 Sheets-Sheet 2 5 MWMW NG N 6 R W -m I H q A M,

Patented Sept. 9, 1947 UNITED STATES PATENT oF- lct:

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John H. Wiggins, Chicago, Ill.

Application June 26, 1944,,lSlerial No. 542,046

"iiilaims.

This invention relates to floating ,tank roof seals of the general type ,or'kind disclosed in my prior U. S.Patent No. 2,318,134, and particularly, the secondary seal .or auxiliary seal of such a structure which is located at the topedge of the side wall shoe.

The main object of my present invention is to prolong the life and reduce the vcost of a secondary seal or auxiliary sealof the generalkind mentioned. v

Another object is to provide a floating tank roof secondary seal, in which the part orporjtion of the seal that rubs against the tank side wall, can be easily replaced or can be adjusted radially to compensate for wear.

Another object is to provide a floating tank H roof secondary seal, in which the part or portion of the said seal that rubs against the tank side wall has a "line contact with said wall and .virtually consists of a flat, horizontally-disposed annular-shaped wiper, arranged so that its outer edge is held in yielding engagement'with the tank side wall, said wiper being -joined or connected with the top edge portion of the side wall shoe by a flexible connecting portion that can be made of a relatively inexpensive material such as air tight canvas, due to the fact thatit does not contact with or rub upon the tank side wall.

And still another object of my invention is to provide a secondary seal of the general construction last referred to, in which th-e tank wall contasting portion andthe co-acting flexible portion that joins said contacting portion to the side wall shoe, are combined a novel manner that enables said tank wall contacting portion to be adjusted .or replaced without disturbing said flexible connecting :portion. Other 'obiects and desirable features of my invention will be hereinafter pointed out.

Figure l of the accompanying drawings is a iragmentary, top planview of a secondary seal embodying my present invention,

Figure 2 is a fragmentary, elevational view of said seaLlooking outwardly {from the center of the floating roof on which said seal is used.

,.Figure is rawertical sectional view, taken on theline3-3 of Figure '2.

Figure 4 is an elevational view of the structure shown. in Figure 3, looking outwardly from the centerof the floating roof.

Figure 5 is a vertical sectional view, on a reduced scalashowing the tank side wall, the floating roof, thei-s'ide wall shoe, the primar seal, and the secondary seal which constitutes my present invention; and l Figure 6 is an enlarged, vertical sectional view .of the secondaryseal The secondary seal shown in my prior Patent No. "2,313,134, previously referred to, is formed by a flexible sealing element extending upwardly from the top edge of the side wall shoe, and maintained in an upright position by rockable carriers or an equivalent, radially-movable means on the sidewall shoe, that holds saidfiexible sealing element in rubbing contact or in engagement with the "tank side wall at apoint above the top edge of the side wallpshoe. The improved secondary seal which constitutes my present invention, is distinguished from the secondary seal shown in my said patent, principally in that it comprises, v

(1) A top rubbingportion or wiper that has a substantially line contact with the tank side wall and which is pressed outwardly against the tank side wall by outwardly-movable rockable carriers or an equivalent radially-movable means mounted on the side wall shoe;

(2) A iiexiblejai-r-tight, curtain-like element whose function is to join or bridge the gap or space between said rubbing portion and the top edg e of said shoe, and

(3) Means at the upper ends of said carriers tor clamping the wiper to the curtain-like element andseouring' both of said parts to the carriers. p f

In general "form, the rubbing portion orjwiper, above mentioned, consists of an easily-stretched, substantially flat ring member or annulus arranged horizontallywi th its outer' edgein engagement with the tank side wall, and the flexible connecting portion, above mentioned, consists of a curtain hanging downwardly from said rubbing portion and attached at its lower-end to the top edge of th side wall shoe. The only portion of the secondary seal that is subjected to wear is the outer edge of the ring-shaped wiper or rulebing portion that contacts the tank side wall. The curtain-like connecting portion that joins said rubbing element to the side wall shoe, is disposed so that it does not contact the tank side wall, and hence, it is not subjected to wear.

In order to produce an inexpensive secondary seal that has a long life, i prefer to construct the two above mentioned portions of the seal as separate units, and attach them to the carriers or equivalent supporting means on the side wall shoe, in such a manner that the wiper or tank side wall rubbing portion can be adjusted radially to compensatefor wear and can also be removed and replaced, without disturbing the connection between the curtain-like connecting portion of the seal and the carriers which sustain it. Generally, the rubbing portion will consist of a substantially flat, horizontally-disposed annulus or wiper that extends preferably unbrokenly around the tank side wall. It may conveniently be constructed from fabric and a moldable substance such as rubber, and may be from one-eighth to three-eighths of an inch in thickness. The curtain-like connecting portion of the seal may be formed of air-tight fabric. Obviously, the two above mentioned portions of the seal, can be attached to or combined with the means that supports them, in various ways, without departing from the spirit of my invention.

In the accompanying drawings, which represent the preferred form of my present invention, the reference character I8 (see Figure designates a floating tank roof, I2 designates the side wall of the tank, I I designates the side wall shoe which may be of any preferred or conventional construction, and I1 designates a conventional primary seal for closing the space between the peripheral edge of the roof I8 and the side wall shoe I I. My improved secondary seal or auxiliary seal (see Figure 6) is composed of a wiper or rubbing portion 5 disposed at a point above the top edge of the side wall shoe I I and arranged so that its outer edge is in rubbing engagement with the tank side wall I2, and a flexible, connecting portion 6 that hangs downwardly from said rubbing portion 5, and in effect, joins the same to the top edge of the side wall shoe II. The rubbing portion 5 is washer-shaped in general outline or form, and is disposed in an approximately horizontal plane. It has sufficient flexibility to permit its outer edge portion to flex downwardly and assume the shape shown in full lines in Figure 6, when the roof rises or moves upwardly relatively to the tank side wall, and to flex upwarly and assume the shape shown in broken lines in Figure 6 during the downward movement of the roof. Said rubbing portion 5 may be supported in various ways without departing from the spirit of my invention. It is herein illustrated as being supported by a plurality of rockable carriers I, which may be of the construction illustrated and described in my prior patent previously referred to, said carriers consisting of vertically-disposed rods whose lower ends are bent laterally to form rock shafts that are mounted in lugs I5 on clamping plates I4 that are attached by bolts l6 to the inner side of the side wall shoe II. Torsion spring I5, shown in Figure 2, exert pressure on the carriers 1 in a direction to swing them outwardly, and thus hold the wiper 5 against the tank side wall. The clamping plates I4 co-act with rings I3 to secure the lower end of the curtain-like connecting portion 6 of my improved secondary seal to the side wall shoe, and said plates also co-act with similar rings I3 to secure the outer edge of the primary seal I! to the side wall shoe I I The carriers 1 are arranged in pairs (see Figure 2) and each pair of said carriers has a horizontally-disposed rod, bar or supporting portion 4 permanently attached to the upper end of same. The bars of the respective groups of carriers I are arranged end to end around the tank side wall, and they co-operate with each other to form a supporting means for the two portions 5 and 6 of the secondary seal. If desired, the gaps or joints between the ends of the supporting rods 4 may be filled with a plastic or semi-plastic substance so as to produce a substantially continuous member that sustains the weight of the ringshaped rubbing portion or wiper 5 and the curtain-like connecting portion 6 of the secondary seal. Each of the supporting bars 4 has permanently attached to same a plurality of horizontally-disposed plates 2 that project inwardly towards the center of the roof, and which form part of clamping devices that are used to attach the portions 5 and 6 of the secondary seal to the rockable carriers I. Thus as shown in the -drawings, a movable clamping plate I is disposed directly above each of the horizontally-disposed plates 2 and bolts 9 provided with nuts I0, are provided for drawing the clamping plates I downwardly so that they will exert a clamping pressure on bars or rods 3 that are positioned on the top side of the wiper or rubbing portion 5 of the seal, in vertical alignment with the supporting bars 4 on the rockable carriers 1. In assembling the structure, the upper end of the flexible, curtain-like element 6 of the seal is first layed upon the supporting bars 4 and retained in position thereon by clamping devices 8 carried by the horizontally-disposed plates 2. The wiper or rubbing portion 5 is then superimposed on the part of the flexible element 6 that extends over the supporting bars 4, and thereafter, the clamping rods'3 are arranged in operative position, and the nuts I0 are tightened so as to securely clamp the two portions 5 and 6 of the secondary seal between the supporting bars 4 and clamping bars 3. After the wiper 5 has Worn down, it may be adjusted outwardly by loosening the nuts I0 slightly, pulling said wiper 5 outwardly, and then tightening the nuts I0. It will be noted that this adjustment of the wiper or rubbing portion 5 to compensate for wear, can be effected without disturbing the other portion 6 of the seal. Preferably, the terminal portions of the clamping plates I that overhang the clamping bars 3, project outwardly far enough beyond the supporting bars 4, to form stops I that are adapted to strike against the tank side wall in the event the wiper 5 becomes excessively worn, thus preventing the hangers 1 from moving outwardly to such an extent or degree as to cause the portion 6 of the seal to be damaged by rubbing against the tank wall until a hole forms in said portion 6.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent, is:-

1. In a secondary seal for floating tank roofs, the combination of a side wall shoe, a horizontally-disposed, annular-shaped wiper arranged with its outer edge in contact with the side wall of the tank at a point above the top edge of the side wall shoe, a curtain-like element extending downwardly from said Wiper and attached at its lower end to said side wall shoe, radially-movable carriers on said shoe provided at their upper ends with horizontally-disposed supports over which the upper end portion of said curtain-like element extends, the wiper being superimposed upon the portion of said curtain-like element resting on said supports, and means co-operating with said supports for frictionally holding the wiper in radially-adjustable relation with said curtain-like element and with the supports on said carriers.

2. A structure of the kind described in claim 1, in which the supports on the carriers consist of horizontally-disposed, bar-like parts arranged end to end so as to form a substantially continuous supporting means for theflexible, curtainlike element that extends circumferentially around the tank side wall.

3. A structure of the kind described in claim 1, in which the means that frictionally holds the wiper comprises adjustable clamps carried by the supports on the carriers and provided with parts that are adapted to act as stops that prevent the carriers from moving outwardly far enough to cause the curtain-like element to rub against the tank side wall.

4. In a sealing structure for the space between a floating tank roof and a tank side wall, the combination of a side wall shoe, a wiper formed by an annular-shaped, horizontally-disposed member having a flexible outer edge, outwardly-movable supports for said wiper mounted on said shoe so as to exert a radial outward thrust on said wiper and press the flexible outer edge of same against the tank side wall at a point above the top edge of said shoe, and a curtain-like, flexible sealing element bridging the space between said shoe and wiper and attached substantially gastight to said parts.

5. A structure of the kind described in claim 4, in which said outwardly-movable supports are provided with means for clamping the upper end portion of said curtain-like element to said wiper at a point some distance inwardly from the flexible outer edge of said wiper.

6. A structure of the kind described in claim 4, in which said outwardly-movable supports are provided at their upper ends with clamps that hold lapped portions of said curtain-like element and wiper in substantially gas-tight engagement.

7. A structure of the kind described in claim 4, in which said outwardly-movable supports are provided at their upper ends with portions that project forwardly beyond the point at which the upper end of said curtain-like element is joined to the Wiper, which forwardly-projecting portions are adapted to co-act with the tank side wall to prevent said curtain-like element from rubbing on said wall in the event the wiper becomes excessively worn.

JOHN H. WIGGINS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,318,134 Wiggins May 4, 1943 1,529,767 Briers et al Mar. 17, 1925 1,668,792 Wiggins May 8, 1928 1,900,904 Berger Mar. 14, 1933 2,354,629 Wiggins July 25, 1944 1,463,268 Hufi Jul 31, 1923 

